Method of conditioning air



Dec. 26, 1939. KAUFMAN 2,184,998

METHOD. OF CONDITIONING AIR Filed June 24, 1936 2 Sheets-Sheet 1 WM? 41M M EE 614; [H fl Dec. 26, 1939. H. J. KAUFMAN METHOD OF CONDITIONINGAIR Filed June 24; 1956 2 Sheets-Sheet 2 F/a Z.

flea 7 INVENTOR.

W a flamz Patented Dec. 26, 1939 UNITED STATES PATENT OFFICE 2,184,998METHOD OF CONDITIONING AIR Hiram Joseph Kaufman, Detroit, Mich.

Application June 24, 1936, Serial No. 87,027 2 Claims. (o1. 183-4) Thepresent invention relates to a method of conditioning air andparticularly tothe use of comparatively cheap. hygroscopic by-productssuch as calcium chloride for the dehumidification 5 of air. a r

An object of the invention is to provide a method of using hygroscopicmaterials for dehumidiflcation which is economical in its operation andcontrollable to give the desired results.

Another object is to provide a method of using hygroscopic material fordehumidification in which the treated air is passed in predeterminedproportions along different paths in contact with solid and liquifiedmaterial and then commingled.

hygroscopic material for dehumidification in which air is flowed alongdifferent paths, at least one containing solid material and anotherliquefled material, and balancing the flows of air so as 20 to give thedesired humidity when commingled with a minimum of liquification of thesolid material.

Referring to the drawings: Fig. 1 is a diagram, showing the aircondition- 25 ing and solution re'concentrating apparatus, the roomsto'be air conditioned, and the accessories necessary therefor.

- Fig. 2 is 'a section through the air passages of 1 A further object isto provide a method of using 24 working oppositely to the said damper22.

the solid dehydrators and through the solution 30 dehydrators.

Rig. 3 is a transverse section through the solid from the space I intothe duct II in contact 'with the thermostat I2 and into the return ductI3. Air is also drawn from the space l4 into the duct |5 in contact withthe thermostat l6 and into the said return duct l3 in contact with the50 humidostat I1 and the thermostat l8 and discharged to the exteriorair through the duct l9 controlled by the damper or passed through therecirculated air duct 2| controlled by the damper 22 and into the inletduct 23. Fresh air 5 is drawn from outside through the duct 24controlled by the damper 25 into the said inlet duct 23.

The said damper 20 is operated by'the lever 25 the pivot 21 and the rod28. The said damper 22 is operated by the lever 29 and the pivot 30which 5 is attached to the said rod 28. The said damper 24 is operatedby the lever 3| the pivot 32 and the said rod 28 which operates thethree said dampers at the same time with the said dampers 20 and Air isdrawn from the said duct 23 into the space 33 and proportioned into twostreams by means of the dampers 34, 35, 36, 31, and 38, operated by thelevers 39, 4|], 4|, 42, and 43, attached to the pivots 44, 45, 48, 41,and 48', which are attached to the rod 49. The said dampers 34 and 35work oppositely to the said dampers 36, 31, and 38, and are moved bymeans of the said rod 49 attached to the pivot 50 of the'damper motorlever 5| which is moved by the damper motor 52 around the pivot 53.

Air passing the said dampers 34 and 35 contacts the cooling coil 54 inthe space 55, then through air passages 55 in the hygroscopic solid 51into the space 58 (the said air passages 56 are shown in another view)'contactingthe'cooling coil 59, then through air passages 60, Fig. 3, inthe hygroscopic solid 6| into the space 52 passing the cooling coil 63and into the space 54.

Air passing the dampers 36, 31, and 38 passes through the space 55between the trays 66 containing hygroscopic solution 6 1, through thespace 83 between the trays 69 containing hygroscopic solution 81,through the space I0, through the filter and resistance unit II, andpasses the said cooling coil 83 into the space 64.

Air is drawn from the space 64 through the duct 12 by the fan 13 drivenby the motor 14 and discharged into the duct 15, where it is dividedinto two flows one of which passes through the duct 15 controlled by thedamper 1'! into the said space H) and the other passes through the duct18 controlled by the damper 19 into the said space M.

The said damper 11 is operated by the lever 88 45 the pivot 8| the rod82 the pivot 83 and the damper motor lever 84 which is moved by thedamper motor85 around the pivot 86. The said damper 19 i operated by thelever 81, the pivot 88, the rod 89, the pivot 90, and the damper motorlever 9| which is moved by the damper motor .92 around the pivot 93. e

Extremely dry air is drawn from the space62 through the duct 94 andnormally dry air is drawn from the space ll through the duct 95 into theEduct 96 intovthe space 91 between the trays 98 containing hygroscopicsolution 61 into the space 99 through the duct I00 into the heatexchanger IOI in contact with the coil I02 containing hygroscopicsolution 61 by the fan I03 driven by the motor I04 and discharged to theatmosphere through the duct I05. The proportionate amounts of extremelydry and normally dry air are controlled by the damper I06 which is movedby the lever I01, the pivot I08, the rod I09, the pivot H0, and thedamper motor lever I II which is moved by the damper motor 2' around thepivot II3.

Hygroscopic material, in solid form, 51 and 6|, is periodically fed intothe hoppers H4 and H5 through the doors II 6, H1, and II8 and slidesdown the containers H9. The upper portion I20 of each of the saidcontainers 9 is formed of solid metal to keep the air from contactingthe said hygroscopic material 51 and GI in order to prevent thehygroscopic solids from caking together due tothe absorption of moisturefrom the air and to allow the free flowing of the hygroscopic solidsdown into, the said containers I I9 from the said hoppers H4 and H5. Thelower portion I2l of the said containers I I9 is formedv of wire clothor perforated metal to allow vapors to pass from the air to thehygroscopic material. The said containers I I9 are divided into cells bythe vertical members I22 which hold the sides in their normal shape andhave smooth surfaces exposed to the hygroscopic material to allow it tosettle down in the said containers II9 due to the melting efiect causedby, absorbing vapors from the air, thereby allowing fresh hygroscopicmaterial to slide into the said containers II9 from the said hoppers H4and H5.

Hygroscopic solution flows down the sides of the said containers II9 tothe collecting pans I23 and I24, then downthe drains I25 and I26 andzigzags on thesloping trays 66 and 69, at right angles to the air flow,to the collecting tank I21. The freshly dissolved hygroscopic materialforms a saturated solution which gradually becomes diluted dueto vaporsabsorbed from the air passing between the trays 66 and 69.

The purpose of the filter and resistance unit 1! is to equalizethestatic pressure loss of the two air flows through the apparatus.

Diluted hygroscopic solution '61 passes through the strainer I28 intoand 'down the pipe I29 through the coil I02 of the heat exchanger IOI,

then through the pipe I30 into the perforated .tank I32 of the solutionevaporator I33. The

said solution evaporator I33 is provided with the overflow pipe-I34 toallow the accumulated excess of solution to waste away. The amount ofexcess solution increases and decreases with the amount of freshhygroscopic. material added, which increases and decreases with theamount .of extremely dry air required to regulate the humidity to thedesired degree.

Reconcentrated hygroscopic solution I35 flows down to the circulatingpump I36 through the pipe I31 and is discharged through the pipe I38,

the ,check valve I39 to the branch pipes I40 and I4I into the drainpipes I25 and I26 where it is mixed with the fresh hygroscopic solutionand drainsto the trays 66 and 69 where it flows zigzag over the saidtrays 66 and 69 as before described.

Cooling water is supplied to the system through the pipe I42 through thebranch pipe I43 to the said cooling coil 63 and discharged through thepipe I44 controlled by the motorized valve I45 to the waste pipe I46.Cooling water is also taken from the pipe I42 by the branch pipe I41tothe cooling coil 59 and discharged through the by the motorized thesaid pipe I38 where it is mixed with the reconcentrated hygroscopicsolution I35. In case this supply of tempered water is not sufiicient toprevent the humidity from going below the said predetermined degree,then the temperature of a the said tempered water is increased in thesaid storage tank I52 by means of .heat supplied through the steam orhot water heating coil I56 controlled by the motorized valve I51, toincrease the vapor pressure of the reconcentrated hygroscopic solutionin order to prevent the absorption of moisture from the air by the saidreconcentrated hygroscopic solution.

Electric power is supplied to operate the system by the positive wire I58 controlled by the switch I59 and the negative wire I60 leading to thelow voltage transformer I'6I with branches taken oif for the pump andfan motors. Power is supplied to the main fan motor 14 by the positivewire I62 and the negative wire I63, to the auxiliary fan motor I04 bythe positive wire I64. and the negative wire I65, and to the circulatingpump motor I36 by the positive wire- I66 and the negative wire I61 andthese motors. are simultaneously started and stopped by the closing andopening of the said switch I59. A positive wire I68 is taken from thesaid low voltage said damper motors 52, 85, 92, and H2 and the motorizedvalves I45, I50, and I54, but this connection is not shown on thedrawings. wire circuits consisting of one positive wire and I pipe I 48to the cooling coil 54 and discharged 4 Three two negative wires aretaken from the saidv damper motors and motorized valves to thepreviously mentioned thermostats and humidostat at an angle at the endstransverse to the air flow to obstruct the air flow as little aspossible, to attain intimate contact between the air and the hygroscopicsolution at all points, and'to direct the flow of the hygroscopicsolution transversely to that of the air. The air flow over the toptrays 66 and 69 is made equal to that between the said'trays vby meansof the baflies HI and I12.' The air flow under the said trays 66 and 69is made equal to that between the said scopic solution surface exposedto the air stream.

The amount of dehydration in the second stage solid dehydrator is thatdue to the lowering of the air temperature effected by the cooling coil59. The solution dehydrators are proportioned to the solid dehydrat'orswhich they serve. Fig. 3 shows the lower edge bent down to form a dripat the alternate sides of the trays 66 and 69;

which is shown in plan in Fig. 5. This drip edge is open the greaterportion of the length which prevents the accumulation of dirt or othersediment and is notched at regular intervals to break up the surfacetension of the solution and cause it to drip in a series of smallstreams in order to distribute the solution evenly over the surface ofthe trays immediately under and to expose the maximum amount of solutionsurface to the action of the air stream. Fig. 4 shows the cellarrangement 'of the second solid dehydrator which is typical of thefirst solid dehydrator. Fig. 6 is a plan of the tray 98 of the solutionevaporator I33 showing the notched drip edge similar to that of thetrays '66 and 69 of the solid dehydrators. Fig. 8 shows the solutionevaporator I33 with the solution supply pipe I30, and perforated pipeI3I, the trays 98 with the ends bent similar to the trays 66 and 69 andfor the purpose of obstructing the air flow as little as possible and todirect the flow of the solution transversely to that of the air Fig. 8shows the trays 98 of the solution evaporator I33, with the lower edgeof said trays bent down to form the drip edge with notches as describedfor Fig. 6. The solution flows zigzag on the said trays 98 at rightangles to the air fiow.

The operation of the system to control temperature and humidity,beginning with a normal air condition is as follows: on a risingtemperature of the air in the return duct I3, the thermostat I8completes a circuit by means of the positive wire I 68 and the negativewire I13 to close a switch to supply power to open the motorized valveI45 to allow more cooling water to pass through the supply pipe I42, thebranch pipe I43, the cooling coil 63, the pipe I44, and the waste pipeI46, to lower the temperature of the air supplied to the spaces I andI4, and on a lowering of the temperature of the air in the said returnduct I3, the said thermostat I8 completes a circuit by means of thepositive wire I68 and the negative wire I14 to close a switch to supplypower to close the said motorized valve I45 to reduce the amount ofcooling water allowed to pass through the said cooling coil and pipes toincrease the temperature of the air supplied to the said spaces I0 andI4. On a rising temperatureof the air in the duct II, the thermostat I2completes a circuit by means of the positive wire I68 and the negativewire I15 to close a switch to supply power to move the damper 11 bymeans of the damper motor 85 to increase the amount of cool air suppliedto the said space I0, and on a lowering of the temperature of the air inthe said duct II, the said thermostat I2 completes a circuit by means ofthe said positive wire I68 and the negative wire I16 to close a switchto supply power to move the said damper 11 by -means of the said dampermotor 85 to decrease the amount of cool air supplied to the said spaceI0. On arising temperature of the air in the duct I5, the thermostat I6completes a circuit by means of the positive wire I68 and the negativewire I11 to close a-switch to supply power to move the damper 19 bymeans of the damper motor 92 to increase the amount of cool air suppliedto the space I4, and on a lowering of the temperature of the air in thesaid duct I5, the said thermostat I6 completes a circuit by means of thesaid positive wire I68 and the negative wire I18 to close a switch tosupply power to move the said damper 19 by means of the said dampermotor 92 to decrease the amount of cool air supplied to the said spaceI4. On a rising humidity of the air in the returnduct l3, the humidostatI1 completes a circuit by means of the positive wire I68 and thenegative wire I19 to close a switch to supply power to move the mixingdamper I06 bymeans of the damper motor I I 2 to increase the proportionof extremely dry air and to decrease the .proportion of the normally dryair supplied to the solution evapor ator I33 to increase the amount ofevaporation, then, after a period of time, mechanism within the saiddamper motor II2 completes a circuit by means of the postive wire I68and the negative wire I80 to close a switch to supply power to open thedampers 34 and 35 and to close the dampers 36, 31, and 38 by means ofthe damper motor 52, then, after a period of time, mechanism within thesaid damper motor 52 completes a circuit by means of the positive wireI68 and the negative wire I8I to close a switch to supply power to openthe motorized valve I50 to increase the amount of cooling water passingthrough the supply pipe I42, the branch pipe I41, the cooling coil 59,the pipe I48, the cooling coil 54, the pipe I49, and the waste pipe I46,to reduce the humidity, and on a lowering of the humidity of the air inthe said return duct I3, the said humidostat I1 completes a circuit bymeans of the positive wire I 68 and the negative wire I84 to close aswitch to supply power to move the said mixing damper I06 by .means ofthe said damper motor 2 to decrease the proportion of extremely dry airsupplied to the said solution evaporator I33 and to increase theproportion of normally dry air supplied to the said solution evaporatorI33, then, after a period of time mechanism within the said damper motorII2 completes the circuit by means of thesaid positive wire I68 and thenegative wires I83 and I84 to close a switch to supply power to closethe said dampers 34 and 35 and to open the said dampers 36, 31, and 38,then, after a period of time, mechanism within the said damper 'motor 52completes the circuit by 'means of the positive wire I68 and thenegative wires I82, I83, and I84 to close a switch to supply power toclose the said motorized valve I50.

In case the humidity of the air in the said return duct I3 falls belowapredetermined degree, the said mechanism within the damper motor II2completes a circuit by means of the positive wire I68 and the negativewire I85 to close a switch to supply power to open the motorized valveI54 to allow tempered water to be taken from the pipe I44 through thepipe II the storage tank I52 the pipe I53 and the check valve I55 intothe pipe I38 to increase the vapor pressure of the reconcentratedhygroscopic solution I35, and, after a periodof time, mechanism withinthe said motorized valve I54 completes a circuit by means of thepositive wire I68 to close a switch to supply power and the negativewire I86 to open the motorized valve I51 to supply steam or hot water tothe coil I56 to further increase the vapor, pressure of the saidtempered water to further increase the vapor pressure of thereconcentrated hygroscopic solution I85, and on an increasing humidityof the air in the said return duct I6, the said humidostat I1 completesa circuit by means of the postive wire I68 and the negative wire I19 toclose a switch to supply powerto move the mixing damper I 06 to decreasethe proportion of normally dry air and to in-v crease the proportion ofextremely dry air supplied to the solution evaporator I33, and, after aperiod of time, mechanism within the damper motor I I 2 completes acircuit by means of the positive wire I68 and the negative wires I19 andI81 to close a switch to supply power to close the said motorized valveI54 to shut ofi the supply 4 of tempered water to the saidreconcentrated solution I35 to reduce the vapor pressure of the saidreconcentrated hygroscopic solution, and, after a period of time,mechanism within the said motorized valve I54 completes a circuit bymeans of the positive wire I 68-and the negative wires I19, I81, and I88to close a switch to supply power to close the said motorized valve I51to decrease the vapor pressure of the said tempered water. The dampermotor shafts are rotated and the valve stems are raised and lowered bymeans of low voltage, alternating current, shaded pole, variable speedmotors and reducing gears which are immersed in oil and are reversibleat any point of the damper or valve travel. The power to operate thesemotors is supplied by the positive wire I68 and the negative wire I69.The time required for reversing the position of the dampers and valvesis varied by changing the speed of the motor. The direction of rotationof the motors is controlled by switches located within the mechanism ofeach motor and these switches are operated by the thermostats andhumidostat which under conditions of high temperature or humiditycomplete a circuit through the positive wire I68 and one of the negativewires to close one of the switches to complete a circuit through thepositive wire I68 and the negative wire I68 to move the damper motor orvalve in one direction and which under conditions of low temperature orhumidity completes a circuit through the positive wire I68 and the othernegative wire to close the other switch to complete a circuit throughthe said positive wire I68 and the said negative wire I68 to move thedamper motor or valve in the opposite direction, the first'two circuitsbeing broken by the change in temperature or humidity, which changes theaction of the thermostatic or humidostatic element and which changesfirst the control circuit and then the motor circuit. The damper levershafts and motorized valve shafts have cams which operate limit switchesto stop the motor when the damper or valve has reached the end of thetravel in either direction. The primary damper motor and motorized valveshafts have a cam at one end of the damper or valve travel which isadjustable in position and which makes a contact through the positivewire I68 and one negative wire to close a switch to supply power throughthe positive wire I68 and the negative wire I 68 to rotate the secondarydamper motor or motorized valve shaft in one direction and another camon the opposite end of the damper or valve travel I68 and the negativewire I68 to rotate the secondary damper' motor or motorized valve shaftin the opposite direction. Similar cams on the secondary damper motorand motorized valvev shafts operate similar circuits and switches tooperate the tertiary damper motor and motorized valve shafts in similardirections. The sped of the damper and valve motors is adjustable and iscontrolled by restricting the ofl flow in the oil immersed motormechanism. The phrase after a period of'time refers to the time requiredfor the primary or secondary damper and valve shafts to rotate from theposition where they previously stopped to the point of the travelrequired by the thermostat or humidostat before a change in the actionof the said thermostat or humidostat occurs. v

The previously described dampers and valves can also be operated by lowvoltage alternating current or compressed air motors of the dia-\ phragmtype whichare normally held in an open or closed position by means of aspring and are moved in the opposite direction by the operation of theelectric motors or compressed air diaphragm motors. The spring tensionis adjusted so that the least effort is required to change the directionof the first stage damper or valve and the greatest effort is requiredto change the direction of the last stage damper or valve. After theconditions of temperature or humidity have been reached the last stagedamper or valve changes back to its normal position first and the firststage damper or valve changes back to its normal position last, which isoppositeto that upon which the description is based, but which will notmaterially change the results.

It is not intended to limit the automatic control of the dampers andvalves to the particular means described, which is manufactured by theBarber Colman Company, Rockford, Illinois, U. S. A., nor to claim anyinvention in the mechanism'within the said damper motors ormotorizedvalves. They, like fans and pumps, are necessary mechanicalparts of an air conditioning system and the detailed description isgiven in order' to enable those skilled in the art to make and use thesame. I

It is intended that this invention is not limited to the use of calciumchloride alone, but that it may be also used for commercial anhydrouscalcium chloride, commercial dihydrate calcium chloride, magnesiumchloride, or other hygro-Q humidity'of approximately 28 per cent and theair in contact with dihydrate calcium chloride would have a relativehumidity of approximately 5 per cent. The practical limits ofdehydration are assumed as 40 per cent for air in 10 contact with asaturated solution, and 15 per cent for air in contact with thedihydrate calcium chloride. It is possible to vary the rela-' tivehumidity of the combinedair. flow by varying the proportions of the airflow exposed to the 7 matic.

saturated solution andto the 'dihydrate solid to produce air with from15 to per cent relative humidity.

The absolute humidity of the air in contact with the solid particles ofhygroscopic material is further reduced by lowering the vapor pressureof the hygroscopic solid by cooling the air previous to contacting thesaid hygroscopic solid in each step to lower the temperature of the saidhygroscopic solid. I I

By making one storage space common to both hygroscopic solids andsolution, in which the filling can be done at convenient periods, thefilling of the containers with the hygroscopic solids is automatic, andthe supply of hygroscopic solution to the trays as well as that of thereconcentrated hygroscopic solution is also auto- It is also apparentthat the hygroscopic solids will be held in proper place until dissolvedby the vapors in the air and then will automatically drain through thesolution carrying members to the collecting tank and carrying with thesolution whatever vapors, colloids, pollens, and solids that may havebeen removed from the air due to contacting hygroscopic and adhesivesurfaces of solution. The purpose of the raised drain outlet is to causethese solids to settle in the said collecting tank from which they canberemoved.

Air passing through the solid dehydrators has the latent heat convertedinto sensible heat in two steps and sensible heat removed in two stepswhich produces extremely dry air with a lowered relative humidity, aloweredabsolute humidity, a lowered total heat content or wet bulbtemperature, and an increased dry bulb temperature. Air passing throughthe solution dehydrators has latent heat converted into sensible heatwhich produces normally dry airwith a slightly lowered relativehumidity, a slightly lowered absolute humidity, a constant total heatcontent or wet bulb temperature, and a slightly increased dry bulbtemperature.

Under normal conditions the number'of grains of moisture to be removedper pound of air circulated may vary from a few grains up to 12 grains..A few grains of moisture may be removed'ifrom a pound of air by thesolution dehydrators in case all of the air is directed through thesolution dehydrators for the smaller load. The number of grains ofmoisture removedfrom a pound of air by the solid dehydrators may bethree times that required per pound oi. air circulated which requiresthat one third of the total amount of air circulated must be drawnthrough the solid dehydrators without consideration of the amount ofwork being done by the solution dehydrators.

The normally dry air from the solution dehydrators may have a relativehumidity of 40 per cent at a wet bulb temperature corresponding to thatof the entering air and may absorb suflicient moisture from the solutionin the solution evaporator to increase the relative humidity of the airup to '70 per cent at the same wet bulb temperature.

The extremely dry air from the solid dehydrators may have a relativehumidity of 20 per cent at a wet bulb temperature several degrees belowthat of the entering air and may absorb suificient moisture from thesolution in the solution evaporator to increase the relative humidity ofthe air up to '70 per cent at a constant wet bulb temperature.

As previously stated, the number of grains of water to be removed perpound of air in the dehydration process may vary from a few up. to 12,the number of grains of water per pound of air that may be absorbed bythe norma ly dry air from the solution dehydrators in the solutionevaporator may be as high as 15 under the conditions stated, and thenumber of grains of water per pound of air that may be absorbed by theextremely dry air from the solid dehydrators in the solution evaporatormay be as high as 30 under the conditions stated.

What I claim is:

1. A method of air conditioning, which comprises drawing air from one ormore enclosures, selectively directing the air in varying proportionsalong two separate courses defining separate drying zones disposed inparallel dependent upon the degree of dehumidification desired,subjecting the air in one course to direct contact with solidhygroscopic material to liquify the same, draining said liquifiedhydroscopic solution into said other course to bring the same'intocontact with air passed along said second course, and directing theconditioned air from said courses into a common course to commingle thesame for discharge into said enclosures.

I 2. A method of air conditioning a flow of air which comprisesdirecting a portion' of the air along one course While subjecting it'todirect contact with solid hygroscopic material to liquify the same toover dry said portion for the purpose desired, directing another portionof air along' a separate and distinct course While subjectin; it todirect contact with liquified hygroscopic material removed from saidfirst course to under dry said second portion for the purpose desired,comm'ingling said portions and directing the same along a common coursefor discharge into an enclosure, and balancing said portions toobtainair of the desired humidity in said common course with a minimum ofliquification of said solid material in said first course, and a maximumof dilution of said liquified material in said second course.

l-IIRAM JOSEPH KAUFMAN.

